[WIP] Add incomplete class to handle duplicate emails

lib/galaxy/model/migrations/data_fixes/user_table_fixer.py

@@ -45,3 +45,16 @@ def _generate_next_available_username(self, username):
         while self.connection.execute(select(User).where(User.username == f"{username}-{i}")).first():
             i += 1
         return f"{username}-{i}"
+
+
+class EmailDeduplicator:
+
+    def __init__(self, connection):
+        self.connection = connection
+
+    def run(self):
+        """
+        Deduplicate user emails by generating a unique value for all duplicates, keeping
+        the email of the most recently created user unchanged.
+        """
+        # TODO